The Internet is fast becoming a versatile media for communication. Devices using Internet Protocol (“IP”) are able to meet a variety of communication needs, including telephone calls and video conferencing. Even analog telephones can communicate over the Internet using a gateway that serves as an interface between the analog domain and the digital domain. However, communications involving IP devices may occasionally suffer from impairments. For example, a user at one endpoint of the communication session may receive echoes of the user's own speech, which is an inconvenience and a source of confusion for the user. To control this and other impairments, IP devices often use non-linear processes.
Conventional non-linear processes include non-linear gain control and comfort noise generation implemented by voice activity detection and echo cancellation devices. Although these non-linear processes help manage impairments, they may also create impairments of their own. One example of such impairment is erroneous attenuation of communication signals. Erroneous attenuation sometimes occurs when IP devices are in half-duplex mode, which means allowing transmission in only one direction at a time.